In two kingdom classifications, there was no differentiation between the eukaryotes and prokaryotes, unicellular and multicellular and photosynthetic and non-photosynthetic organisms. In the two-kingdom classification the bacteria, blue-green algae, fungi, mosses all were included under the kingdom Planate. It placed together groups which widely differed from each other. A large number of organisms did not fall into any category. Thus, the two-kingdom classification was insufficient and inadequate.
The five kingdom classification resolved the issues as it considered other factors like cell structure, mode of nutrition, thallus organisation, reproduction and phylogenetic relationships. This system of classification placed the organisms into five different categories. All the prokaryotes were placed under Kingdom Monera. The unicellular eukaryotes were placed under Kingdom Protista. The fungi occupied a separate kingdom. Thus, it proved to be adequate and much better than the two-Kingdom classification.